This disclosure generally relates to tools used in the manufacture of composite structures, and in particular, to a graphite composite tape supply and backing paper take-up apparatus for use in conjunction with a high speed, composite tape laminating machine that enables the use of larger tape supply reels and substantially wider tapes, thereby achieving higher lamination rates and lower material costs in the lamination process.
The demand for large, complex composite parts, such as are used, for example, in composite air frames, is growing rapidly. These parts are typically produced by laying parallel strips of a composite tape, e.g., unidirectional graphite fiber tape impregnated with an uncured resin (a “prepreg”), immediately adjacent to each other on a forming tool, then curing the resin. The growing demand is typically being satisfied by suppliers in one of two ways: 1) by purchasing multiple, current-technology laminating machines, or 2) by developing machines that can laminate parts at a higher rate. The second option, developing high speed laminating machines, can, in the long run, actually reduce tooling, facility, and equipment costs.
Existing tape supply solutions all rely on a relatively narrow tape that is “level wound” onto long spools, i.e., in the same manner as a line is wound onto a fishing reel equipped with a reciprocating pawl. In order to level-wind the material, the tape width is limited to 0.5 inch. The narrow tapes cannot be “single-wound,” i.e., in the manner of a movie film, onto reels of a corresponding width because the diameter of the reels would have to be increased substantially to accommodate a useful amount of tape thereon, and hence, would have an unacceptably high inertia.
A “dancer,” i.e., a secondary roller disposed adjacent to the spool and over which the tape unspools, is commonly used to absorb the shock applied to the tape by accelerating the spool, and a brake acting on the spool is used absorb the inertia of the spool when decelerating the spool. The existing solutions use active control of the braking force applied to the supply spool, and passive control of dancer movement. Because the existing solutions do not actively control the dancer position, they have great difficulty controlling large supply reels with varying inertias.
Thus, the existing solutions are limited to the use of spools that are level-wound with laminating tape that is limited to a maximum width of 0.5 inch. The total number of tape strips that a laminating machine can manage when laying a swath of tape is limited, and using a narrow tape creates a relatively small total swath width, thereby requiring a large number of passes of the laminating head of the machine over the layup tool to laminate a part having a relatively large area. Therefore, higher lamination rates could be achieved if multiple strips of wider strips of tape could be used reliably.
Accordingly, there is a need in the industry for an apparatus that enables a composite tape laminating machine to lay multiple tapes having greater widths reliably, and thereby achieve a substantially increased laminating speed.